1. Field of the Invention
This invention relates to a process for sealing secondary batteries. More particularly, it relates to a process for repairing defective seals of secondary batteries.
2. Description of the Piror Art
Casings for secondary batteries consists of containers and covers. Usually the containers and covers are molded of a thermoplastic material such as polystyrene, polymethacrylate, polyamide, polyolefin, polyvinyl chloride, polymethacrylate, and the like. After the battery is assembled, the space between the container and cover is sealed with a sealant compound.
Most sealant compounds are not entirely satisfactory because they are not able to provide a crackface seal during the total useful life of the battery. This is particularly true for secondary batteries exposed to vibration, very low or very high temperatures, and used for applications requiring a rugged long life device. Over the course of years the sealant compound may, for a variety of reasons, become brittle and often breaks, forming cracks and holes which allow solvent to evaporate and electrolyte to escape. For such batteries to remain useful the holes and cracks, i.e., the defective seal, must be repaired.
The known processes for repairing defective seals require the battery to be disconnected, removed from operation, and possibly moved to a different site for the repair to be done safely. The The process of the present invention provides for the repair to be done safely while maintaining the battery in operation and on-site.